Browsing by Author "Diaz De Apodaca, E."
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Item Films of chitosan and chitosan-oligosaccharide neutralized and thermally treated: Effects on its antibacterial and other activities: Effects on its antibacterial and other activities(2016-11-01) Fernández-de-Castro, Laura; Mengíbar, Marian; Sánchez, Ángela; Arroyo, Leire; Villarán, Mª Carmen; Diaz De Apodaca, E.; Heras, Ángeles; Villarán, Ma Carmen; Tecnalia Research & Innovation; Alimentación SostenibleThe present study focuses on the effects of heat and neutralization treatments on solubility, water vapour permeability and antimicrobial activity of chitosan (Ch) and chitosan/chitooligosaccharide (ChO)-based films. ChO films showed stronger antimicrobial activity against Escherichia coli, Bacillus cereus, Staphylococcus aureus, Serratia liquefaciens and Lactobacillus plantarum than Ch films, indicating that this effect is attributed to the presence of chitooligosaccharides (COS) in the films. Heat and neutralization treatments decreased significantly the solubility of chitosan films and gave rise to a sharp loss in their antimicrobial activity. The incorporation of COS in chitosan films increased the inhibitory effect against the studied microorganisms without affecting significantly the water vapour permeability of the films. Thus, it is possible to get a more insoluble chitosan film with high antimicrobial activity by means of incorporation of COS combined with heat or neutralization treatments.Item Production of PHB from Chicory Roots - Comparison of Three Cupriavidus necator Strains(2015-06-03) Haas, C.; Steinwandter, V.; Diaz De Apodaca, E.; Maestro Madurga, B.; Smerilli, M.; Dietrich, T.; Neureiter, M.; Alimentación Sostenible; BIOECONOMÍA Y CO2Chicory roots from hydroponic salad cultivation are an abundant food residue in Navarra (Spain) that are underutilized to date. Aiming at a holistic utilization of resources, we report here the first process using chicory root hydrolysate for the production of poly([R]-3-hydroxybutyrate) (PHB). The polymer can be used for packaging material made for the locally produced vegetables. In the first step, we developed a pre-treatment process to obtain a hydrolysate, which contained 34 g L-1 sugars and 0.7 g L-1 total Kjeldahl nitrogen. This hydrolysate was used as fermentation substrate for three PHB-producing strains. Cupriavidus necator DSM 428 reached a dry biomass concentration of 11.3 g L-1 with a PHB content of 66 % in dry mass within 5 days. C. necator DSM 531 yielded 3.5 g L-1 dry biomass containing 46 % PHB within the same period. C. necator DSM 545 was superior over the other two in that 14.0 g L-1 of biomass containing 78 % PHB after only 3 days were obtained. These results show that even within the same species, the productivities on natural substrates are very different. The produced polymers were extracted using chloroform, and several thermo-physical parameters are in good accordance with published data. Overall, our holistic approach and the encouraging results prove that chicory roots are a viable fermentation substrate for PHB-production.